1. Field of the Invention
The present invention relates to self-tanning cosmetic products and methods. More particularly, a naturally-occurring light-responsive fluorescent agent and a self-tanning agent are combined in a cosmetic composition which may be detected with a matched light source, thereby indicating the presence and extent of composition coverage.
2. Description of the Prior Art
Naturally tanned skin is generally accepted to be the product of the physiological development and distribution of melanin, a skin pigment. When skin is exposed to radiant energy, especially light in the UV region, melanin is delivered to the skin surface. There it accumulates and oxidizes, giving the skin a darkened patina. This process is believed to afford a degree of natural protection for the skin against harmful UV overexposure.
Tanned skin is accordingly associated with outdoor activity, and is aesthetically desirable for many people. Unfortunately, it is not always possible to spend the requisite time under radiant exposure to develop a naturally tanned appearance. Further, exposure to UV radiation in sufficient quantity to develop a tan has many associated health risks. These include erythema, actinic skin damage, premature skin aging, and development of skin melanomas. Additionally, many people have skin complexions which do not tan readily. For example, the skin of some people with fair complexion reacts to UV radiation by developing small patches of color, or freckles, rather than a continuous tan.
For these reasons, cosmetic self-tanning agents have been developed in the prior art, and have achieved wide commercial acceptance. Self-tanning agents produce a color change in the skin without sun or other intense radiation exposure. U.S. Pat. Nos. 2,949,403 issued Aug. 16, 1960 to John T. Andreadis et al.; 5,318,774 issued Apr. 12, 1994 to Brian A. Crotty et al.; and 5,302,378 issued Jun. 7, 1994 to Noelle C. Alban et al. disclose various self-tanning agents, formulations, and methods of use. Their disclosures are incorporated herein by reference. In conventional self-tanning products, color change is not immediately developed, but gradually darkens the skin over a period of time from a few hours to a day or so, depending on the self-tanning agent and its formulation.
Upon developing, the color becomes fixed on and in the upper layers of skin, and like natural tans, may not be removed by normal bathing. The developed color slowly fades over several days to weeks, again simulative of natural tans. Unfortunately, if the self-tanning agent is applied to undesired areas of the skin, or if areas of the skin are not uniformly covered, the aesthetic quality of the resultant tan will be marred by imperfections. These imperfections will only show when color has developed in the skin and become very difficult or impossible to correct, due to the desired resistance to removal of these products, as noted above. Besides exercising care in applying self-tanning formulations, the prior art is silent as to this problem.
Cosmetic formulations which include fluorescent pigments or dyes are known. These are typically used in face or body paints. Lipsticks and makeup wherein the fluorescent material produces brilliance, whitening, or color for a desired aesthetic appearance. Fluorescent compounds dispersed in sun-screening products have also been the subject of earlier patents, U.S. Pat. No. 3,988,437 issued Oct. 26, 1976 to Hugh Bradner, describes a sun-screening product in which fluorescent material is dispersed to absorb the harmful radiation of the sun and convert it into less harmful rays to tan the human skin. These compositions are formulated with inert carriers. No description is made in this patent of combining fluorescent materials with other active ingredients, nor using the fluorescent materials as indicators, since these materials fluoresce outside the visible spectrum.
Further, lamps which produce photo-luminescence in exposed surfaces are known in the art. Typically, blacklight sources (which emit long UV light) have been used to reveal fluorescent pigment in paints. Marquees, and various static structures, painted with fluorescent pigment and illuminated with blacklight, were prevalent in the 1920s and 1930s. Soviet Pat. SU 1,627,938 issued Feb. 15, 1991, describes a light that produces a photo-luminescent response in relation to the degree of contamination of wood. Cosmetic use of such systems are not revealed in the prior art.
U.S. Pat. Nos. 4,818,491 issued Apr. 4, 1989 to James D. Fariss and 5,196,705 issued Mar. 23, 1993 to Paul T. Ryan each teach sun exposure monitors which utilize light-responsive fluorescent material. Again, these patents are not directed to cosmetic compositions, nor do they disclose the use of self-tanning agents.
U.S. Pat. No. 5,626,839 issued May 6, 1997 to Virginia Scales-Medeiros, co-applicant herein, provides an admixture of self-tanning agent and fluorescent materials that clearly indicate the extent and uniformity of coverage when the composition is applied to skin. However, that patent did not disclose naturally-occurring fluorescent materials, which have since been determined to be preferred for a number of reasons, including market acceptance, availability, safety of use, and biodegradability.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.